California's requirement for medical supervision of applicators regularly handling Toxicity Category I and II organophosphate and carbamate cholinesterase-inhibiting pesticides is examined from a policy perspective by the California Department of Health Services (CDHS). Changes to increase the effectiveness of medical supervision and solutions to a number of practical implementation problems are discussed, including the pesticides which should be monitored, the use of individual cholinesterase baselines, the enzymes to be measured, and the frequency of cholinesterase testing.